The Brain and Behavior Discovery Institute of the Medical College of Georgia, in the context of the program for development of new therapeutic agents for stroke, submits this Innovative Research Proposal entitled Mini-plasmin: Pre-Clinical Evaluation of a Novel Thrombolytic Strategy for Stroke. The rational for this project is to develop a novel and alternative, but high risk approach to acute stroke. It represents a unique translation of molecular insights into pre- clinical model of stroke and a paradigm shift in to how thrombolysis in stroke may be approached. Stroke is the third leading cause of death in the U.S. and the leading cause of disability amongst adults. With the aging population, the incidence of stroke is expected to rise. Despite the testing of over 70 agents in clinical trials, only one drug, the recombinant tissue plasminogen activator (TPA), has been approved by the FDA for the treatment of ischemic stroke. However, there are major concerns regarding the safety of TPA. Moreover, TPA is often ineffective. Due to those concerns, TPA is used on only 2% of ischemic stroke patients. The high failure of TPA to achieve efficient and safe reperfusion has led to the abandonment of ischemic stroke as a target disease by the pharmaceutical industry and neurovascular research. Clearly, more effective and safer agents along with more creative approaches are required. The fundamental mechanism of ischemic stroke is the occlusion of a cerebral vessel by a fibrin rich blood clot (thrombus). We aim to elaborate a novel thrombolytic agent for direct recanalization of brain arteries, which is not involved via different pathways independent of thrombolysis. These studies will characterize for the first time the effect of mini-plasmin structure on thrombolysis of stroke and will serve as a pilot data for further evaluation of a novel chimeric plasmin with desirable properties. The main idea is to demonstrate the feasibility of efficient thrombolysis by the agent that can synergistically combine 1) the fibrin targeting, 2) the direct fibrinolytic activity and 3) the following ability to neutralize systemic plasmin inhibitor. We propose to test mini-plasmin molecule in both in vitro and in vivo models. We believe that mini- plasmin may achieve high recanalization rates, lower hemorrhage rates, and higher neuro- protection than TPA. We have assembled a team of experienced basic and clinical stroke researchers and experts in pharmacology and drug delivery to approach the problem. This project deals with a central problem in the field of acute stroke therapy, and we believe that improved thrombolytic therapy and outcomes for ischemic stroke should be directly translated into reduced mortality and morbidity. PUBLIC HEALTH RELEVANCE: Project Narrative Ischemic stroke is a major health and socio-economic problem, affecting many individuals. Relevant to this reality, investigators in stroke research are looking into efficient and safe thrombolytic therapy to improve the recovery from stroke. In this project we propose a novel thrombolytic agent and plan to determine its efficacy for the treatment in an experimental model of thromboembolic cerebral ischemia.